When using a runtime virtual texture with a resolution of greater than 2^24 we can start to see a lack of precision in sampling when the sampling UVs get closer to 1.
To see this we need to be using using adaptive virtual texture to allow for a texture with sufficient resolution. But the issue is not with adaptive virtual texture itself.
The issue comes from the lack of precision in floating point as we near the value of 1. At around 1 we have a precision of 2^-24.
Use the attached RVT_TestCase project.
The runtime virtual texture stores a grid which is sampled.
Observe that the grid looks good near the origin.
But at the far side of the volume the grid appears corrupted.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-155365 in the post.